1. Field of the Invention
The apparatus of the present invention relates to devices for inserting and removing probes to and from the interior of a high-pressure vessel or flowline while under pressure, utilizing an entry valve typically installed onto a perpendicular branch of said high-pressure vessel or flowline for this purpose. Said entry valve isolates pressure below the entry valve and within the high-pressure vessel or flowline, thereby eliminating interruption of the fluid flow. More particularly, the present invention relates to the independently operating design of the apparatus, and the ability of a single apparatus to utilize a variety of probes including probes requiring conveyance of chemicals, pneumatic signals, or electronic signals to the inserted probe, in addition to sacrificial probes only requiring conveyance of the probe itself.
2. General Background of the Invention
In the technology of the integrity of vessels and flowlines, there has developed a technique whereby a variety of sacrificial probes, chemical injection devices, pneumatic devices, and electronic devices are used to monitor and treat certain properties of the high-pressure fluids transported within said high-pressure vessels and flowlines. Said devices require intermittent removal from said high-pressure vessels and flowlines under pressure for replacement, maintenance, or inspection. Sacrificial probes are pre-weighed samples of metal similar to the metal used in the fabrication of the high-pressure vessel or flowline. Sacrificial probes are exposed to the high-pressure fluids within the high-pressure vessel or flowline for a predefined period, and then removed for processing. The weight loss of the probe experienced during exposure to the high-pressure fluids is then converted to a mills-per-year corrosion rate estimate that can be applied to the high-pressure vessel or flowline. This method of monitoring corrosion has been in use for decades, and although new techniques for monitoring corrosion are available, the practice continues to be very common. Newer methods of monitoring corrosion and many other aspects of the high-pressure fluids contained within the high-pressure vessel or flowline require means to convey an electronic or pneumatic signal to an external device to process the collected data. These devices also require periodic retraction from the high-pressure vessel or flowline for routine maintenance or calibration. In relation to either of the methods mentioned for monitoring the properties and condition of the high-pressure fluids, there is the need for application of chemical compounds to offset the effects of the high-pressure fluids on the high-pressure vessel or flowline. Examples of probes used for this purpose include chemical injection quills that prevent immediate contact with the inner surface of the high-pressure vessel or flowline before the chemical can be absorbed into the high-pressure fluids, and chemical atomizers that reduce the particle size of the chemical for improved contact with and absorption into the high-pressure fluids.
In the current state of the art, sacrificial probes, chemical injection probes, and electronic devices require an individual apparatus to convey each of the different types of probes and devices, and are typically bulky and require additional tools to complete the insertion and retraction process. In such a device, in the current state of the art, an apparatus will utilize an externally attached drive mechanism to push the probe or device into the pressurized vessel or flowline. The drive mechanisms must either be stored, or carried with the operator, in cases where a single drive mechanism is utilized to operate several apparatuses. Said drive mechanisms typically apply force in only one direction to complete the insertion process, and rely on the pressure within the high-pressure vessel or flowline to push the probe or device to the extracted position. The rod or tube utilized in said devices to position the probe in the high-pressure vessel or flowline often accumulate a buildup of debris associated with the high-pressure fluids and are occasionally bent within the high-pressure vessel or flowline by larger debris passing through the high-pressure vessel or flowline. Examples of this debris would include accumulations of precipitated scales, paraffin waxes, and hydrates that form onto the walls of the high-pressure vessel or flowline and detach from the high-pressure vessel or flowline impacting the inserted probe. Under normal circumstances the pressure within the high-pressure vessel or flowline is sufficient to push the inserted probe out of the high-pressure vessel or flowline. The relatively common examples of complications to the extraction process caused by said debris often require a force in excess of the available pressure within the high-pressure vessel or flowline and render the apparatus inoperable. Currently available apparatuses would require the insertion tool to be removed for the application of additional force to complete the retraction of the probe, allowing for periods of non-control of the insertion rod. These periods of non-control can result in an unpredictable release of the insertion rod causing damage to the apparatus, the device, and posing a threat to the individual operating the apparatus.